Root-NFS: Server returned error -13 while mounting /home

1、出现的问题：在开发板上挂载网络文件系统，修改之前的属性：

set bootargs noinitrd root=/dev/nfs nfsroot=192.168.1.106:/home/gab/work/root_fs/fs_mini_mdev ip=192.168.1.17:192.168.1.106:192.168.1.1:255.255.255.0::eth0:off init=/linuxrc console=ttySAC0

2、补充一下，设置bootargs noinitrd的模式为：

root=/dev/nfs
nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
init=/linuxrc console=ttySAC0

3、reset重启uboot，跳过uboot，加载linux内核后，启动文件系统报错：

Root-NFS: Server returned error -13 while mounting /home
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "nfs" or unknown-block(2,0)
Please append a correct "root=" boot option; here are the available partitions:
1f00        256 mtdblock0 (driver?)
1f01        128 mtdblock1 (driver?)
1f02       2048 mtdblock2 (driver?)
1f03     259712 mtdblock3 (driver?)
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)

3、解决方案：

exportfs -a //用来加载所有文件系统

发现设置的共享文件系统目录不支持 NFS export

root@iBOY-ARM:/home/gab# exportfs -a
exportfs: /home/gab/work/root_fs/fs_mini_mdev does not support NFS export

我的分析：

因为该目录位于gab用户下，我试过将该共享目录放在非用户目录下就可以了，将/home/gab/work/root_fs/fs_mini_mdev 复制到 /home目录下，然后在/etc/exports文件里添加：

/home/fs_mini_mdev *(rw,sync,no_subtree_check)

重新 exportfs -a 加载就没问题了